contrast transfer function

It is described by the contrast transfer function.

The oscillations of contrast transfer functions have the form (not including the envelope function):

The square wave result is sometimes referred to as the 'contrast transfer function' (CTF).

Contrast transfer function, in general imaging (see also Modulation transfer function)

The contrast transfer function is the equivalent of the optical transfer function in light that affects images collected in a transmission electron microscope.

The contrast transfer function must be corrected in the images in order to obtain high resolution structures in three-dimensional electron microscopy, especially cryo-electron microscopy.

Complete control of the contrast transfer function, displayed measurement parameters, versatile image editing and ability to detect 256 grey levels are a few of CUE 2's abilities.

Typical test charts for Contrast Transfer Function (CTF) consist of repeated bar patterns (see Discussion below).

The frequency domain representation of the contrast transfer function may often have an oscillatory nature, which can be tuned by adjusting the focal value of the objective lens.

The contrast transfer function can, to some extent, be experimentally approximated through techniques such as Fourier transforming images of amorphous material, such as amorphous carbon.

The phase contrast transfer function (CTF) is a function of limiting apertures and aberrations in the imaging lenses of a microscope.

The combined effects of the imaging conditions are known as the Contrast transfer function (CTF), and can be approximated mathematically as a function in reciprocal space.

It should be noted whenever using a bar target that the resulting measure is the Contrast Transfer Function (CTF) and not the MTF.

Second, the contrast transfer function of BF-TEM is essentially a high-pass filter - information at low spatial frequencies is significantly suppressed - resulting in an exaggeration of sharp features.

One commonly used value is a cut-off value of the contrast transfer function, a function that is usually quoted in the frequency domain to define the reproduction of spatial frequencies of objects in the object plane by the microscope optics.

For example, to improve the contrast in the image the TEM may be operated at a slight defocus to enhance contrast, owing to convolution by the contrast transfer function of the TEM, which would normally decrease contrast if the sample was not a weak phase object.